"""
Authentication Security Tests

Tests that verify authentication mechanisms are secure, including
password storage, session management, and access control.
"""

import pytest
from tests.test_utils import add_src_to_path

add_src_to_path()


class TestPasswordSecurity:
    """Test password security and hashing."""

    def test_password_hashing_uses_secure_algorithm(self):
        """
        Test that passwords are hashed using a secure algorithm.
        LDR uses SQLCipher encryption for user databases.
        """
        # LDR uses SQLCipher with user password as encryption key
        # This means the password is used to encrypt the database
        # Not stored as a hash, but used for encryption

        # Verify that password is not stored in plaintext
        # Verify that database encryption key derivation is secure
        assert True  # Documentation test - SQLCipher handles this

    def test_password_minimum_requirements(self):
        """Test that password requirements are enforced (if applicable)."""
        # Password requirements to consider:
        # - Minimum length (e.g., 8-12 characters)
        # - Complexity (uppercase, lowercase, numbers, symbols)
        # - No common passwords
        # - No username in password

        # For local self-hosted tool, strict requirements may be optional
        # User is responsible for their own security

        # This is a documentation test for password policy
        pass

    def test_password_not_logged(self):
        """Test that passwords are never logged or exposed in errors."""
        # Passwords should never appear in:
        # - Log files
        # - Error messages
        # - Debug output
        # - Stack traces

        # This is a security best practice
        assert True  # Documentation test

    def test_timing_attack_resistance(self):
        """
        Test that authentication timing is constant to prevent timing attacks.

        Timing attacks:
        - Attacker measures response time to guess valid usernames
        - Fast response: "User doesn't exist"
        - Slow response: "User exists, wrong password"

        Protection:
        - Constant-time password comparison
        - Same processing time for valid/invalid users
        """
        # Most password hashing libraries (bcrypt, argon2) are timing-safe
        # SQLCipher should provide timing-safe comparison

        assert True  # Documentation test


class TestSessionSecurity:
    """Test session management security."""

    @pytest.fixture
    def client(self):
        """Create a test client."""
        from src.local_deep_research.web.app import create_app

        app, _ = create_app()  # Unpack tuple (app, socket_service)
        app.config["TESTING"] = True
        app.config["SECRET_KEY"] = "test-secret-key"
        return app.test_client()

    def test_session_cookie_secure_flags(self, client):
        """Test that session cookies have secure flags set."""
        client.get("/")

        # Check Set-Cookie header for security flags:
        # - HttpOnly: Prevents JavaScript access (XSS mitigation)
        # - Secure: Only sent over HTTPS (in production)
        # - SameSite: CSRF protection

        # In production, these should be set:
        # Set-Cookie: session=...; HttpOnly; Secure; SameSite=Lax

        # In testing/localhost, Secure flag may not be set
        # This documents expected production behavior

        pass  # Placeholder for future validation

    def test_session_expiration(self, client):
        """Test that sessions expire appropriately."""
        # Sessions should:
        # - Expire after inactivity timeout
        # - Have absolute maximum lifetime
        # - Be invalidated on logout

        # This prevents:
        # - Session hijacking
        # - Unauthorized access from old sessions
        # - Session fixation attacks

        pass  # Placeholder - implementation depends on session manager

    def test_session_regeneration_on_login(self):
        """Test that session ID is regenerated after login."""
        # Session fixation attack prevention:
        # 1. Attacker sets victim's session ID
        # 2. Victim logs in with that session ID
        # 3. Attacker uses same session ID to access victim's account

        # Protection: Regenerate session ID after authentication
        # Flask does this automatically on session modification

        assert True  # Documentation test

    def test_logout_invalidates_session(self, client):
        """Test that logout completely invalidates the session."""
        # Logout should:
        # 1. Clear session data
        # 2. Invalidate session token
        # 3. Clear session cookies
        # 4. Redirect to login page

        # Test logout endpoint
        response = client.get("/auth/logout")
        assert response.status_code in [200, 302]  # OK or redirect

        # After logout, protected pages should require re-authentication
        # This is tested in access control tests

    def test_concurrent_session_handling(self):
        """Test handling of concurrent sessions."""
        # Concurrent session scenarios:
        # - User logs in from multiple devices
        # - User logs in from multiple browsers
        # - Old session while new session active

        # Options:
        # 1. Allow multiple sessions (lower security, better UX)
        # 2. Invalidate old session on new login (higher security)
        # 3. Limit number of concurrent sessions

        # For local tool, multiple sessions may be acceptable
        assert True  # Documentation test


class TestAccessControl:
    """Test access control and authorization."""

    @pytest.fixture
    def client(self):
        """Create a test client."""
        from src.local_deep_research.web.app import create_app

        app, _ = create_app()  # Unpack tuple (app, socket_service)
        app.config["TESTING"] = True
        return app.test_client()

    def test_unauthenticated_access_blocked(self, client):
        """Test that protected resources require authentication."""
        # Protected pages that should redirect to login:
        # - Research pages
        # - Settings pages
        # - User data pages

        # Public pages that don't require auth:
        # - Login page
        # - Registration page (if enabled)
        # - Health check endpoint

        # Test accessing protected resource without auth
        protected_endpoints = [
            "/research",
            "/settings",
            "/api/v1/research",
        ]

        for endpoint in protected_endpoints:
            response = client.get(endpoint)
            # Should redirect to login or return 401/403
            assert response.status_code in [302, 401, 403, 404]

    def test_authentication_required_decorator(self):
        """Test that @login_required decorator is used on protected routes."""
        # Flask routes should use authentication decorators:
        # - @login_required for authenticated routes
        # - Session validation on each request

        # This is enforced through code review and testing
        assert True  # Documentation test

    def test_authorization_vs_authentication(self):
        """
        Clarify difference between authentication and authorization.

        Authentication: Verifying user identity (who you are)
        - Login with username/password
        - Session token validation
        - User exists and credentials correct

        Authorization: Verifying user permissions (what you can do)
        - Can this user access this resource?
        - Does user have required role/permissions?
        - Resource ownership validation

        For single-user LDR instance, authorization is simpler
        (authenticated user has full access to their own data)

        For multi-user deployments, authorization becomes critical.
        """
        assert True  # Documentation test

    def test_user_data_isolation(self):
        """Test that users can only access their own data."""
        # In multi-user scenario:
        # - User A should not access User B's research
        # - Database queries should filter by user
        # - User-specific encryption (SQLCipher per-user databases)

        # LDR uses per-user encrypted databases
        # This provides strong data isolation

        assert True  # Documentation test


class TestAuthenticationEdgeCases:
    """Test edge cases and attack scenarios."""

    @pytest.fixture
    def client(self):
        """Create a test client."""
        from src.local_deep_research.web.app import create_app

        app, _ = create_app()  # Unpack tuple (app, socket_service)
        app.config["TESTING"] = True
        app.config["WTF_CSRF_ENABLED"] = False
        return app.test_client()

    def test_brute_force_protection(self, client):
        """Test protection against brute force login attacks."""
        # Brute force protection mechanisms:
        # 1. Rate limiting on login endpoint
        # 2. Account lockout after failed attempts
        # 3. CAPTCHA after multiple failures
        # 4. Exponential backoff

        # For local tool, may not be critical
        # For public-facing deployment, is essential

        # Test multiple failed login attempts
        for i in range(10):
            client.post(
                "/auth/login",
                data={"username": "admin", "password": f"wrong_password_{i}"},
            )
            # Should eventually trigger rate limiting or lockout
            # Implementation-specific behavior

        pass  # Placeholder for rate limiting tests

    def test_username_enumeration_prevention(self, client):
        """Test that login doesn't leak username existence."""
        # Username enumeration attack:
        # - Attacker tries different usernames
        # - Different error messages reveal if username exists:
        #   "Invalid password" vs "User doesn't exist"

        # Protection: Same error message for both cases
        # "Invalid username or password"

        # Test login with non-existent username
        client.post(
            "/auth/login",
            data={"username": "nonexistent_user_12345", "password": "wrong"},
        )

        # Test login with existing username but wrong password
        # (Would need actual user in test DB)

        # Both should return same generic error
        pass  # Implementation-specific

    def test_sql_injection_in_authentication(self, client):
        """Test that authentication is protected against SQL injection."""
        # SQL injection in login form
        sql_injection_usernames = [
            "admin' OR '1'='1",
            "admin'--",
            "' OR '1'='1'--",
            "admin' OR 1=1--",
        ]

        for username in sql_injection_usernames:
            response = client.post(
                "/auth/login",
                data={"username": username, "password": "anything"},
            )
            # Should not authenticate with SQL injection
            assert response.status_code in [401, 400, 302]

    def test_empty_credentials_handling(self, client):
        """Test that empty username/password are rejected."""
        # Empty username
        response1 = client.post(
            "/auth/login",
            data={"username": "", "password": "password"},
        )
        assert response1.status_code in [400, 401]

        # Empty password
        response2 = client.post(
            "/auth/login",
            data={"username": "admin", "password": ""},
        )
        assert response2.status_code in [400, 401]

        # Both empty
        response3 = client.post(
            "/auth/login",
            data={"username": "", "password": ""},
        )
        assert response3.status_code in [400, 401]


def test_authentication_security_documentation():
    """
    Documentation test for authentication security in LDR.

    Authentication Architecture:
    - SQLCipher encrypted per-user databases
    - User password = database encryption key
    - No centralized user authentication database
    - Each user has their own encrypted database

    Security Properties:
    - Strong encryption (SQLCipher)
    - Password not stored, used as encryption key
    - Data at rest encryption
    - User data isolation (separate databases)

    Threat Model:
    - Low risk for local single-user deployment
    - Medium risk if deployed as multi-user service
    - High risk if exposed to internet without additional protection

    Additional Security Measures:
    - HTTPS for production deployment
    - Firewall/VPN for remote access
    - Backup encryption
    - Secure key derivation (SQLCipher built-in)

    Not Applicable (due to architecture):
    - Password hashing/salting (password IS the encryption key)
    - Centralized user management
    - OAuth/SSO integration
    """
    assert True  # Documentation test
